Vehicle brake



Dec. 22, 1936.

E. ENGEL VEHICLE BRAKE Filed June 14, 1935 2 Sheets-Sheet l 4 122, 936. E. ENGEL 2,065,176

VEHICLE BRAKE l Filed June 14, 1935 2 Sheets-Sheet 2 atented Dec. 22, 11.936Y

rares PATENT OFFICE VEHICLE BRAKE Application June 14, 1935, Serial No. 26,675

In Germany June 21, 1934 6 Claims.

In the known brake constructions provided with a locking device forholding they brakes in the applied position it is possible for the driver to withdraw the pressure-applying device serv- 5 ing for actuating the brake before he has released the locking device. If this occurs, the continuity ci the braking uid in the pressure cylinder and in the pipe line is interrupted and, in consequence of the production of a vacuum,

i air may pass into the brake conduit from the outside so that an air cushion is produced which detrimentally alects the braking eiect when the brakes are next applied.

The primary object of the present invention is l to avoid this disadvantage and with this object in view the brake actuating mechanism is im proved in that in the reverse motion of pressureapplying device, such as a hand-wheel operating on the piston of a pressure cylinder, the locking device is in the rst place released entirely automatically and then the pressure applying the brakes is withdrawn. This can be attained in that the hand-wheel is axially displaceable on threads provided on its shaft and during this g5 displacement in the rearward rotation rst actuates the means for-.releasing the'locking device.

This actuation canA either be effected directly or indirectly by means of a lever transmission or the like.

In the accompanying drawings which illustrate certain constructional forms of the invention by way of example: l

Fig. l shows one embodiment in partial section.

Fig..2 shows a fragmentary view of a second embodiment and Fig. 3 shows a third embodiment.

In the embodiment according to Fig. 1 the pressure medium for applying the brakes is contained withinV a cylinder I, in which operates a.

piston 2. The piston 2 Vis provided with a hollow internally threaded piston rod in which a spindle 3 is in threaded engagement. To enable rotation of the spindle 3 for displacing the piston 2 within the cylinder I the spindle 3 carries on its free end a bevel gear wheel 4 in which engages a bevel gear wheel 5 fast on a threaded shaft l.

The hand-wheel 6 for actuating the brake is carried on the threaded spindle 1 which is `pro- 59 vided at its outer end, with flange or collar A8, l for limiting movement of hand whee1`6 on shaft 2 "l, whereby when the hand wheel engages the cam 8 its turning movement is applied to shaft 1.

The inner edge I0 of the hand wheel 6 is con- 55 structed in the form of a cam.

(CI. 18S-265) The hydraulic cylinder serving for releasing the brake locking device is shown at Il. The rod I2 attached to the piston operating in the cylinder II carries on one-side a roller I3 which runs on the cam IIJ of the hand-wheel 6.

If for the purpose of applying the brakes the hand-wheel 6 is rotated so as to travel along the spindle I away from the bevel gear wheel 5 then in the first place the hand-wheel travels along the spindle 'I without-rotating the latter until the flange or collar 8 on the spindle isf engaged. Then the spindle l is caused to rotate with the hand-wheel 6 and the spindle 3 is set in rotation by way of the bevel gear wheels 5 and 4 whereby the piston 2 is displaced within the pressure .cylinder I When the brake is to be releasedagain, the hand-wheel 6 is rotated in the opposite direction. It then iirst travels in the axial direction on the threaded spindle 1 so that the coupling flange or collar 8 is disengaged so that initially the spindle 'I and thus the bevel gear wheel 5 remain at rest until the hub of the hand lwheel 6 abuts againstthe hub of the bevel gear wheel 5. The bevel gear wheel 5 is then caused to rotate with the hand-wheel 6 and the brake piston 2 is clisplaced in the other direction within the pressure cylinder I. In the axial movement of the hand-wheel 6 on the threaded spindle I however the cam l0 has occasioned the displacement of the roller I3 and thus of the piston rod I2 and the piston carried thereon in the release cylinder I I, so that the device locking `the brake jaws is vto a cylinder 3| in which there is apiston 32 provided'below with a rack 34.v The rod mechanism 35 leading to the brake jawsV abuts the opposits end of the rack 34 fromthe cylinder 3I in a socket 36. A

The rack 34 may be engaged by a check block '31 which has corresponding teeth 39 and is erts pressure in the cylinder, so that, through the passage 30 pressure arises behind piston 32 in cylinder 3| whereby, through the rod 35,- the brake jaws are applied on the brake drum and the braking is eiected. At this point the check member 31 has its teeth 39 pressed into the rack 34 through the action of spring 40 and firmly retains the piston 32 in the braking position.-

When the brakes are to be released hand wheel 6 is turned backward, whereby it first, moves on a screw spindle 1 before acting on gears 5 and 4. In this rightward movement of the hand wheel 6 the piston II is moved by lever I9 (Fig. 3) in its cylinderA and pressure is thereby produced in the passage 44. This pressure passes to the piston 4I in cylinder 42 and forces it'and the check member 31 to the right, so that the teeth of this member 31 withdrawffrom racks 34 and release them. The check device of the brake is thereby released, and if hand wheel 6 is turned further backward it again draws back the piston 2 in cylinder I through the gears 4, 5 and spindle 3, so that the fluid column in passage 30 can again pass back to cylinder I and pressure on piston 32 ceases. The piston 32 is then subjected to the action of the withdrawal spring, not shown, mounted on the brake jaws, and which is provided on every ordinary brake, and passes back to the initial position, and-thc brake is released. This specific check mechanism is not a. part of the present application, but only control mechanism therefor. l

In order'to make the stroke of the piston rod i2 correspondingly small, the cam I0 can be made correspondingly steep in the axial direction. It

is however also possible to interpose between the f roller I3 and the piston rod AI2 a lever transmission or other transmission mechanism as indicated in the embodiment according to Fig. 2. Here the roller I3 is carried on a lever I 4 vwhich isV pivoted at I6 and engages the piston rod I2 of the release cylinder Il at I5. The resultant lever ratio reduces the displacement of the piston rod I2. Otherwise this embodiment operates precisely in the same way as that described above. In other respects the embodiment of Fig. 2 may be similar to Fig. 1.

In the embodiment according .to Fig. 3 the hand-wheel 6 carries a guide I1 in which engages the end 2li of a lever I9 pivoted at I8. The other end of thisvlever directly engages the piston rod l2 of the hydraulic piston of the locking device.

When the hand-wheel 6 is rotated reversely then it again travels along the threaded spindle 1 and the guide I1 carries the end 20 of the lever I9 along with it so that the other end 2| oi this lever operates on the piston rod I2 of the mechanism for releasing the locking device.` Instead ofthe lever I9 naturally any other transmission arrangement can be employed. Instead of inserting a lever transmission between khandwheel and piston rod, it is possible with a suit able arrangement for the lateral' surface of the hand-wheel to operate directly on the piston rod.

. The mechanism for locking the brakes in applied position" may be similar to that described in connection with the embodiment represented by Fig. 1.V

I claim:-

1. In-'a hydraulic brake system for vehicles a device for locking the brakes in the appliedposition, operating means rotatable in one direction for applying the brakes and in the other direction for releasing the brakes, the initial part locking device.

2. In a vehicle brake system including a device for locking the brakes'in the applied position, control mechanism comprising a threaded shaft rotatable in opposite directions to apply and release the brakes, a hand wheel adapted to screw along said threaded shaft, abutments limiting the travel of said hand wheel along said shaft, and means for releasing said locking de'- vice, said means being engaged by said hand wheel during its travel alongsaid shaft in consequence of rotation c! said hand wheel on said shaft in the same direction as said shaft is rotated for releasing the brakes.

3. In a vehicle brake system including a device ior locking the brakes in the applied position, control mechanism as claimed in claim 2 comprising a cam carried on the hand Wheel, a roller co-operating with said cam, a slidable rod carrying said roller and associated with means for releasing said locking device.

4. In a vehicle brake system including a device i'or locking the brakes in the applied position, control mechanism as claimed in claim 2 comprising a cam carried on the hand Wheel, a roller co-operating with said cam, a-pivoted lever carrying said roller at its vfree end, a slidable rod engaging said pivotal lever at an intertion, operating means rotatable in one direction for applyingy the brakes and in the other direction for releasing the brakes', the initial part ofv the rotary movement f said operating means in said other direction being idle movement for brak-e releasing purposes, but providing axial movement thereoLmeans actuated by said operating means during said idle rotary movement and axial movement' for releasing said locking device, said locking device releasing means comprising displaceable means engaged by the movable brake operating means during its idle motion, and a transmission mechanism coupling said displaceabl means releasing the locking device.

6. In a vehiclebrake system including hydraulic brakes and a device for locking the brakes in the applied position, control mechanism comprising a cylinder containing the hydraulic medium, a piston operating within said cylinder, a. hollow internally threaded rod at" tached to said piston, a rotatable but nontranslatable screw engaging .in said internal thread, a bevel gear wheel secured to said screw, a rotatable but non-translatable threaded' shaft, a bevel gear wheel secured to said shaft and engaging with the iirstv bevel gear wheel, a hand wheel in threaded engagement with said shaft, abutments on said shaftto limit the axial displacement of'said hand wheel, a member engaged and displaced by said hand wheely during its displacement in one direction, and means for releasing the locking ldevice linked. to said member.

l ERNST ENGEL. 

